It is well known that epoxy-resin, one of the thermoset resins, is a high-molecular-weight material having good heat resistance, mechanical properties, electric insulating properties, adhesiveness and weather resistance; and epoxy resin is used as paint, an electric insulating material, a stabilizer for vinyl chloride, a coating and a matrix resin of fiber-reinforced complex material. It may fairly be said that these widely varying industrial applications of epoxy resin have resulted from the development of curing technology; and, thus, the effect of the curing agent on epoxy resin is enormous.
Specifically, epoxy resin requires the use of a curing agent in order to create a three-dimensional net structure; and, therefore, the heat resistance and the final mechanical properties of the epoxy resin may be different depending on the nature of this curing agent. Curing agents having components harmful to the human body (e.g., amine compounds) are frequently used, which results in many problems. The use of such curing agents in combination with additives such as accelerators, plasticizers, fillers, mold-releasing agents, flame retardants, diluents and dyes largely reduces the physical properties of the epoxy resin.
Further, the use of a curing agent comprising an amine (e.g., DDS: 4,4-diaminodiphenylsulfone) may result in decreased processability due to its high viscosity; and, thus, the production of molded products using such a curing agent becomes very difficult.
Recently, the development of high-quality integrated circuits in the course of the development of the electric and electronic industries has required the development of materials for high-performance print-circuit substrates. Furthermore, materials capable of high-density wiring having excellent electric insulating properties, dielectric properties and dimensional stability have been constantly requested. For instance, materials with heat resistance that does not change above approximately 180.degree. C. are are in demand for the large-plate-display industry for applications such as LCD (Liquid Crystal Displays), FED (Field Emission Displays), and PDP (Plasma Display Panels), which are referred to as next generation industries. However, this demand is not being satisfied because the existing epoxy resins have unreliable resistance to high temperatures; and the cost of high-heat-resistant epoxy resins (such as FR-5, bismaleimide triazine resin, or polyimide resin) is still high. The present invention meets the technical demands of industry and solves or ameliorates the problems of the prior art.